1. Field of the Invention
The present invention relates to an ultrasonic system for measuring material constant, that is, the thickness, the diameter or the number of materials, for example, the thickness of a paper, the thickness of a leaf, the diameter of a fiber, or the number of sheets of paper.
2. Description of the Prior Art
Conventional methods for measuring the number of sheets of paper are generally based on mechanical measurements. Accordingly, it is difficult to measure the number of sheets of paper precisely on the instant. A conventional method for measuring the thickness of a paper or the diameter of a fiber is based on mechanical measurements. Accordingly, it is difficult to measure the thickness of a paper or the diameter of a fiber continuously and quickly.